Abstract

The neutron capture cross section of 206Pb has been measured at the CERN
n TOF spectrometer using a setup of two C6D6 detectors. In the energy interval
from 1 eV to 600 keV the cross section is dominated by resonances, which
were analyzed via the R-matrix analysis code SAMMY. In the relevant energy
ranges for stellar nucleosynthesis, i.e., at thermal energies of kT = 8 keV and
kT = 23 keV, the present Maxwellian average cross section differs by 20%
and 9% from the recommended values of Bao et al respectively. From the new
cross section the s-abundance of 206Pb could be reliably determined as 70(4)%.
This result is of importance in order to test and constrain r-process abundance
calculations in the actinide region, because the r-process portion of 206Pb is
dominated by α-back decays of short-lived transbismuth isotopes.